Piston and valve assembly for hydraulic control devices



April 15, 1952 J. G. cATRANls PISTON AND VALVE ASSEMBLY FOR 'HYDRAULIC CONTROL DEVICES Filed Nov. 19, 1948 Willi? lllllll,

IN V EN TOR.'

Jafw 5. 65mm@ Patented Apr. `15, 1952 UNITED PATENT OFFICE PISTONzAND` VALVE ASSEMBLY FOR HYDRh/UIIC` CONTROL DEVICES John G. Cattranis, Syracuse, N, Y.

Application November 19, 1948, Serial No. 60,903

Claims. (Cl, 18S-e536) This invention relates to hydraulic variable retarding devices, as cylinder and; piston dash pots, and has for its object a check and control valve assembly in the piston forcontrolling the flow of fluid through luy-passes from oneA side of the piston to the othertside, whichasseinbly is Dalfticularlyl simple and compact.

The invention consists in the novel features and in the combinatioris and constructions hereinafterset forth and claimed.

In describing this invention, reference is had to the accompanying drawings in which like characters designate corresponding` parts in all the views.

Figure 1 isaside elevation, partly broken` away, of a cylinderand piston retarding device or` dash pot embodying this invention.

Figure 2 is a longitudinal sectional view taken centrally of ligure` 1.

Figure 3 is an enlarged fragmentary sectional View ofthe piston construction showing the check valve and the throttle valve controlling the` flow of iluid through the by-pass from one end of the cylinder to the other when the valves are in normal or` starting position` Figure 4 is a view, similar to Figure 3, showing the position of the valvesV when in fully operated position.

The invention resides in the piston having a by-pass extending lengthwise thereofand opening through the opposite ends or pressure faces thereof, a check valve` in the by-pass to check the flow of fluid in one direction, Vasecond bypass around the check valve, a self-opening throttle valve in the piston and also an operating member in the piston` operable to progressively close the second lay-pass, and means for operating the throttle valve from outside of the cylinder and piston.

One of the features of the invention is the throttle valve mounted to shift axially in a passage in the check valve, the throttle valve beiner formed with a second by-pass leading from the rst by-pass through the outer end or the throttle valve and opening into the cylinder.

The Construction here ShQWn is intended primarily to eontrolthe operation of the knee lock of an artificial leg and operable by the action of the stump of the natural leg in the socket of the artificial leg, or by the contraction and relaxation of thigh muscles, such as the quadriceps tendon, as in my application, Sr. No. 779,011, filed October 10, 1947, now Patent No. 2,568,051, issuedv September 18, 1951.

I and 2 designate respectively the cylinder and piston of a hydraulic retarding device or double 2. acting dash pot, these having relative axial movement, the cylinder I having a bracket 3 at its lower end forconnection to a` iixed point, and the piston 2 having a rod 4 provided with a coupling 5 for pivotal connection to a bracket at the lower end of the socket` of` the leg, the

`pivotal connection being eccentric to the axis `the bore of the cylinder and a reduced portion 8 at one side, as the upper side of the intermediate portion, the reduced portion 8 being spaced from the Walls of the cylinderl providing an annular space 9. The piston is shown as also having a depending portion In on the other side or below the intermediate portion 6. The body and its reduced portions are formed` with an axial bore opening through the lower edge of the reduced portion III and terminating short of the upper end or the body 2, providing a head at II from which the piston rod 4 projects, the bore I2 of the piston rod opening into the bore of the piston body.

I3` designates a cage or casing iitted at one end, as the upper end, into the upper end of the bore of the piston body and depending` into the bore of the piston body but spaced apart at I4 from the wall of the bore to provide an annular chamber,

I5 designates a plug or second casing threading intothe lower endof the piston body and teleseoping on the lower end of the cage I3. Radial ports I6 in the piston body 6 connect the annular spaces 9 and I4 and radial ports I'I con- -nect the radial spaces I4 and the internal chamber i8 in the plug`l5. These spaces 9, I ii, and radial portsn I6, I1, form a by-pass from one end of the'cylinder to the other. The chamber I8 opensthrough the outer end, that is the lower end of the plug I5.

20 designates a'uid pressure operated check valve located to check the ilow of iiuid in one direction, as downwardly, from above the piston through the lower end thereof, this being shown as semi-spherical and coacting with a .seat at 2I on the walls of the chamber I8 where it opens through the lower end of the plug I5.

22 designates the throttlevalve, this being slid- `any suitable manner.

able through a passage at 23 in the check valve, it having an axial bore 24 opening through its lower end and laterally extending ports 25 opening through the periphery thereof and normally opening into the chamber I8. The throttle valve is normally in the position shown in Figure 3, and is shiftable downwardly so that the ports 25 are covered or cut oif` progressively. The throttle valve is also provided with a head 26 seating on the check valve when the throttle valve is fully closed and thus holding the check valve closed. The passage 24 and radial ports 25 constitute a second by-pass around the check valve. The throttle valve may be actuated in It is here shown as self opening and actuated hydraulically to closed position by a piston or plunger 28 in the upper portion of the bore of the casing-I3 and pressed upwardly by a spring 29. The casing communicates with the passage of the piston rod 4, previously referred to, so that any pressure created by the action of the thigh muscles is transferred to the plunger 28 when this device is embodied in a knee lock mechanism of an artificial leg. When actuated, the plunger 28 is pressed downwardly and through a coupling 30 actuates the throttle valve towards closed position an amount corresponding to the tension or relaxation of the thigh muscles.

In order to adjust the effective cross sectional area of the by-pass, a gate 3| in the form of a sleeve threads on the upper reduced portion of the body 6 of the piston and is adjusted axially to carry its lower edge 32 in position to cut off more or less the radial passages i6. `This sleeve or gate does not entirely fill the annular passage 9. One way of initially adjusting it is to pull the piston upward until the lug 33 interlocks on one side or the other of a key 34 at the lower end of the head 35 of the cylinder l and the piston rod is given a partial turn and thereby turning the upper end of the piston body 6 in the sleeve while the gate is held. from turning movement. In order to limit this relative turning movement, a radial pin 33 on the upper portion of the piston body 6 moves in an arcuate slot 39 in the gate.

This piston and valve assembly is particularly compact and the valve operation sensitive to such small forces as are generated by relative movement between the stump of a leg and the socket of the artificial leg, such as'are generated by the tension and relaxation of thigh muscles.

What I claim'i-s:

1. A piston and valve assembly for hydraulic control devices which comprise a cylinder and a piston having relative axial movement, the piston having a by-pass opening through its pressure faces at opposite ends thereof, a check valve in the by-pass to check the flow of fluid in one direction, a second by-pass in the piston around the check valve, a self-opening throttle valve operable to close the second by-pass, and means in the piston for operating the throttle valve, the throttle valve being mounted to shift axially in an axial passage in the check valve and being formed with the second by-pass leading from the first by-pass through the outer end of the throttie valve, and the operating means'being located in the piston in axial alinement with the throttle valve, the throttle valve having a head for coacting with the check valve to press against and hold the check valve closed when the throttle valve is fully closed.

2V. A piston and valve assembly forY hydraulic control devices which comprise a cylinder and a piston having relative axial movement, said piston comprising a body having an axial bore opening through one end, a check valve casing disposed in said bore and forming a substantially axial chamber in the piston, a second casing mounted in axial alinement in the bore of the piston, a pressure operated check valve in the check valve casing and coacting with a seat therein, an axially movable throttle valve in said chamber and movable through an axial bore in the check valve, the throttle valve having an axial `bore opening through its outer end and Aradial ports opening into said chamber, a spring-returnable, throttle-operating member axially movable in the second casing and connected to the throttle valve, a by-pass extending lengthwise of the piston from one pressure side thereof to the other including said chamber, the bore and ports of the throttle valve constituting a second bypass around the check valve, and means for operating the throttle valve operating member from outside of the cylinder and piston. Y

3. A piston and valve assembly for hydraulic control devices which comprise a cylinder and a piston having relative axial movement, said piston comprising a body having an axial bore opening through one end, a check valve casing disposed in said bore and forming a substantially -axial chamber in the pistori, a second casing mounted in axial alinement in the bore of the piston, a pressure operated check valve in the check valve casing and coacting with a seat therein, an axially movable throttle valve in said chamber and movable through an axial bore in the check valve, the throttle valve having an axial bore opening through its outer end and radial ports opening into said chamber, a spring-returnable, throttle-operating member axially movable in the second casing and connected to the throttle valve, a by-pass extending lengthwise of the piston from one pressure side thereof to the other including said chamber, the bore and ports of the throttle valve constituting av second bypass around the check valve, andrmeans for operating the throttle valve operating member from outside of the cylinder and piston, and an adjustable gate on the piston to vary the effective cross sectional area of the rst by-pass. Y

4. A piston and valve assembly for hydraulic control devices which comprise a cylinder and a piston having relative axial movement; said piston comprising a body having an intermediate portion for coacting with the walls of the bore of the cylinder, a reduced portionyat one side of the intermediate portion providing an annular space, a hollow piston rod connected tothe reduced portion, the piston also having an axial bore extending through its other end and also extending into the reduced portion, a check valve casing and a second throttle-valve-operating member casing located in axial alinement in said bore, the rst casing providing a chamber within the piston and having radial ports opening into a second annular space between said casings and the wall of the bore of the piston, the piston having radial ports connecting the first and the second annular spaces, a pressure operated check valve in said chamber and coacting with a seat at the outer end of the chamber. a throttle valve extending axially through the check valve and axially into the chamber and formed with an axial passageopening through its outer end, and radial ports opening into the chamber, a springreturnable 4throttle-valve-operating plunger in the second casing connected to the throttle valve, and means for operating said plunger from outside of the cylinder and piston.

5. A piston and valve assembly for hydraulic control devices which comprise a cylinder and a piston having relative axial movement; said piston comprising a body having an intermediate portion for coacting with the walls of the bore of the cylinder, a reduced portion at one side of the intermediate portion providing an annular space, a hollow piston rod connected to the reduced portion, the piston also having an axial bore extending through its other end and also extending into the reduced portion, a check valve casing and a second throttlevalveope'rating member casing located in axial alinement in said bore, the rst casing providing a chamber within the piston and having radial ports opening into a second annular space between said casings and the Wall of the bore of the piston, the piston having radial ports connecting the first and the second annular spaces, a pressure operated check valve in said chamber and coacting with a seat at the outer end of the chamber, a throttle valve extending axially through the check valve and axially into 6 the chamber and formed with an axial passage opening through its outer end, and radial ports opening into the chamber. a spring-returnable throttle-valve-operating plunger in the second casing connected to the throttle valve, and means for operating said plunger from outside of the cylinder and piston, and an annular gate adjustable axially of the reduced portion of the piston to vary the effective size of the radial ports between the annular spaces.

JOHN G. CATRANIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,455,691 West May 15, 1923 1,810,233 Walden June 16, 1931 2,305,291 Filippi Dec. 15, 1942 FOREIGN PATENTS Number Country Date 290,983 Great Britain Nov. 15, 1928 

